Use "module" instead of "main" when exposing ESM.

In order for this package to work out of the box with webpack, we need to either name the index.js "index.mjs" (and not have a file extension, e.g. "esm/index") or use the "module" field in package.json. Otherwise it's not easily possible to load this through webpack without transpiling it.

Author: fubhy

.gitignore

@@ -82,4 +82,4 @@ typings/
 
 # End of https://www.gitignore.io/api/node
 
-esm/
+dist/

package.json

@@ -2,13 +2,16 @@
   "name": "rxjs-hooks",
   "version": "0.3.2",
   "description": "React hooks for RxJS",
-  "main": "esm/index.js",
+  "module": "dist/esm/index.js",
+  "main": "dist/cjs/index.js",
   "author": "LongYinan <[email protected]>",
   "license": "MIT",
-  "typings": "esm/index.d.ts",
+  "typings": "dist/cjs/index.d.ts",
   "sideEffects": false,
   "scripts": {
-    "build": "rm -rf esm && tsc -p src/tsconfig.json --outDir esm",
+    "build": "yarn build:esm && yarn build:cjs",
+    "build:esm": "rm -rf dist/esm && tsc -p src/tsconfig.json --module es2015 --target es5 --outDir dist/esm",
+    "build:cjs": "rm -rf dist/cjs && tsc -p src/tsconfig.json --module commonjs --target es5 --outDir dist/cjs",
     "lint": "tslint -c tslint.json -p src/tsconfig.json",
     "start": "webpack-dev-server --config ./tools/webpack.config.js --progress --color",
     "test": "NODE_ENV=test jest --no-cache --ci"